If politicians can get away with majority of the crimes that would damn an average citizen, what do they have to fear for?

I don't get it. Time after time we read about these politicians that dangle over the grill about to be punished for something, but then they usually don't. Very few do but a lot of the time, they don't. And they seem to get scared about the punishment when they don't factor in the odds and chances that they'll get away with it.

So what's the deal?